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Y W. A. CAMPBELL.

REVBRSING VALVE. Y No. 324,222. Patented Aug. 11, 1885..

UNITED STATES PATENT OEEICE.

VILLIAM A.

CAMPBELL, OF EAST SAGINAW, MICHIGAN, ASSIGNOE OF ONE- HALF TO A. F. BARTLETT & OO., OF SAME PLACE.

REVERSlNG-VALVE.

SPECIFICATION forming p'art of Letters Patent No. 324,222, dated August 11, 1885. i Application tiled April 29,1885. i (No model.)

To all whom it may concern:

Be it known that I, WILLIAM A. CAMPBELL, of East Saginaw, in the county of Saginaw and State of Michigan, have invented new and useful Improvements in Reversing-Valve Attachments to Steam-Engines; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, which form a part of this specification.

This invention relates to new and useful improvements in twin-cylinder steam-engines; and the invention consists, mainly, in the construction and arrangement of the valves and valve-gear for correctly distributing the steam and controlling the movement of the valves by means of a lever in the hands of the operator, so as to adapt the engines for operating a saw-mill carriage, a hoist, an elevator, or for similar use requiring a constant and quick reversal of the engines and absolute control of their speed.

In the drawings which accompany this specification, Figure lis an elevation of the twin-engine, showing the side on which the valves and valve-gear are located, the valves of one engine being shown in section to show their construction and arrangement. Fig. 2 is a side elevation showing the main shaft with its connections. Fig. 3 is an enlarged view of the steam chest and Valves. Fig. 4t is a detail speciiicallyreferred to hereinafter.

A A are the cylinders of two engines, sym metrically alike in all parts, and inclined so as to form a right angle with each other, and having their frames suitably connected and sup.-

Y ported so as to form a single structure.

B is the main shaft, supported on top of the frame and common to both engines. C isa crank or crank-disk on the main shaft. D D arethe connecting-rods ofthe engines, attached to the wrist of the crank, and E E are two valve-eccentrics, which actuate the valves of the engines, all these parts being of known construction and operation.

The valves and valve-gear are constructed and arranged as follows:

F is a hollow piston slide-valve operating in a cylinder steam-chest, G, from vwhich the usual ports, a a, lead into the enginc-cylimler.

This piston slide-valve has its seat formed like an ordinary D-valve, and it regulates the distribution of steam into the cylinder precisely in the manner of such a valve. Owing to its form, it is steam-balanced.

H is the exhaust-passage, which communicates with the exhaust side of the slide-valve, and I is the live-steam passages, through which the steam passes into the steam-chest G. J is another steam-chest secured to the steamchest G, and having the steam-supply pipe K leading into it. This steam-chest incloses a cylinder, L, in which the piston slide-valve M is seated. The cylinder L is open at both ends, and has the three ports N O P. The port N communicates through the exhaust-passage H with the exhaust side of the slide-valve F.

The port O communicates through the passage I with the steam-space in the steam-chest G, andthe portPleadsinto the exhaust-pipe Q.

The piston-valve M is a cylindrical D slidevalve. It operates in connection with the ports N O P in the following manner: In one of its two extreme positions (which is shown in the drawings) it connects the exhaust-port N with the exhaust-port O, and gives the livevv steam free access through the port P into the steam-chest G. In its opposite position the valve M connects the port P with the exhaustport O, and opens the exhaust-port N to the live steam. Thus by reversing the valve M from the position shown in the drawings the exhaust side of the valve F becomes the steam side, and vice versa. The steam being thus reversed in the cylinder, lthe piston will also be reversed.

As the two valves M must be operated alike, they are connected together by a system of levers and connecting-rods, arranged as follows: The valve-rod of each valve is pivotally connected to a connecting-rod, E. Each of these connecting-rods is connected to one end of a bellcrank lever, S, the other ends of which are connected together by a connectingrod, T. The respective arms of the bell-crank levers S are of equal length, and they form the same angles with their respective connectingrods. This arrangement gives the valves M. an equal throw.

U is a rock-arm secured to one of the bell- IOO controls the valves M simultaneously.

By the above-described arrangement the weightof the valves M and their valve-gear is balanced.

It will be observed that by moving the valve M from one of it-s extreme positions toward the opposite one the steam is first gradually throttled until at n1id-position, when it is entirely cut off from the cylinder; then steam is again admitted in a reverse direction and gradually increases until the valve is again fully opened. Thus the speed and direction of the engine absolutely depend on the position and movement of the valve M. It will be further observed that the valve M, at whatever position it may be placed, is always perfectly steam-balanced, so that it can be moved by hand without the slightest exertion. The perfect action of the valve M in these respects is a necessary condition for its practical use in an engine for operating a saw-mill carriage or hoist, as the work of the engine is here entirely and constantly guided by the hand of an operator, whose work depends largely on the ease and promptness with which he can control his engine.

As far as the construction and operation of the valves F and M are concerned, it is obvious that they are equally applicable to single engines, and I clai'ln their application as such as well.

For engines of large size I interpose between the hand'lever and the valve-gear a steampiston for operating the reversingw'alve by steanrpowei, as shown in Fig. 4, in which the hand-lever operates a slide-valve, m, on the steam-eylindera. When the steam is admitted on both sides of the piston, the engines are at rest, and if the valve m is thrown over to one side or to the other the engines are running in one direction or the opposite. By means of this arrangement but little movement and power are required by the operator to control his engines.

What I claim as my invention isl. The combination, with twin engines arranged at right angles to each other to form two sides of a triangle, with a single supplypipe at the base, and a single main shaft at the apex, as shown, o`f a main slide-valve for each engine, and two reversing-valves intcrposed between the supply-pipe and the main valve, and arranged with their gear to counterbalance each other,l as set forth.

2. In a twin-cylinder engine, the combination of the reversing slide-valves M M, connecting-rods R R T, and the bell-cranks S S, arranged in two connecting sets, each adapted to counterbalance the other, with a single actuating handlever, W, substantially as described.

3. In a twineylinder engine having valves F operated from a single shaft, the balanced reversing piston slide-valves M M, each arranged to eounterbalanee the other, and each having a cylindrical seat open at both ends, and provided with ports N O P, combined with the steam-el1ests J, forming a steam-passage to both ends of the valve, and with a single operating mechanism for moving both valves simultaneously in the same direction, as set forth.

4. The combination of the steanrbalanccd reversngslide-valvesM,withtheireonnectinggear arranged to counterbalance the weight of valves and gear, all arranged substantially as described.

5. In atwin-cylinder engine havinga single main shaft and feed-pipe, the combination, with the valves E and connections with the main shaft, ofthe balanced reversing-valves M, the rods R R T, bell-crank levers, and operating mechanism, as U V NV, arranged to counterbalance, as set forth.

WILLIAM A. CAMPBELL.

Witnesses:

H. S. SPRAGUE, CHARLES J. HUNT. 

